This Lightfoot ammonia refrigeration compressor was made in 1918 by the Lightfoot Refrigeration Company Limited, based in Fareham, Hampshire.

This large 17 ½” bore x 34” stroke double acting compressor runs at around 300 rpm, and is attached via flat/rope belt to a Siemens 265 hp electric motor. The complete machinery takes up around 11 feet by 30 feet, and 16 feet tall, totalling at 28 tons.

The 19th century saw the development of mechanical refrigeration through the use of vapour-compression technology, pioneered by chemists and engineers such as Carl von Linde, Thomas Bell Lightfoot. Vapour-compression works by cyclically evaporating refrigerant gases like C02 and ammonia to absorb the surrounding heat of a specific space, piping the gas to another location and then compressing these gases via a condenser to release the heat. Vapour-compression systems share many similarities to motor engines in cars and other vehicles and could be throttled to control the rate of compression, and by extension rate of refrigeration.

Ammonia refrigeration compressors became integral in many commercial and industrial applications such as international shipping and storage, with the earliest design of commercial ammonia compressors dating back to the 1870s.

This Lightfoot ammonia compressor is a double acting reciprocating type which, like an automobile engine, uses sets of alternating valves to compress and expand refrigerant gases at high pressures.

This simple design can be almost indefinitely scaled up to meet different demands. This came at the cost of being noisy and inefficient compared to later high-speed reciprocating compressors which were develop not long after this large Lightfoot ammonia compressor was installed at the Alexandra docks in Liverpool in 1918. Whilst it was likely powered by steam engines to begin with, this compressor was eventually powered using a Siemens electric motor drive.

Despite being outdated, this ammonia compressor continued to refrigerate the meat and fish stores of the Union Cold Storage company at the Alexandra docks in Liverpool until the late 1970s.